1. Field of the Invention
The present invention relates to a method of making iron (including pig iron and steels) by melting iron scrap without consuming electric power or petroleum. The invention encompasses an apparatus suitable for practicing the method.
2. State of the Art
Melting of iron scrap for producing steels, particularly special steels, is usually carried out in electric furnaces. It is assumed that there is little probability of improvement in the generation of electric power, and that the power cost will successively increase. Also, the relationships between petroleum-supply and demand is getting tighter, and therefore, it is not advantageous to generate thermal electric power with consumption of petroleum, or even to directly use petroleum fraction for steelmaking.
We have intended to establish a technology of iron making using coal or coke, a stable supply of which can be expected for the present, or other carbonaceous materials of lower grades, instead of using electricity or petroleum.
With respect to the iron making using carbonaceous materials, cupola iron making using coke has been commercially practiced. The cupola iron making requires lumps or blocks of coke of a high strength and suitable sizes so that the coke may support the charged materials to ensure gas flow in the furnace. This poses a limit from a materials viewpoint, and a disadvantage in cost. Also, a cupola is inherently a furnace for making cast iron and gives only molten iron containing 3 to 4% carbon, namely, pig iron. Therefore, if it is intended to make steels, further oxidation refining (decarburization) and reduction refining using another furnace such as a convertor are necessary.